The project includes studies on the biochemistry of hormone-sensitive adenylate cyclase in a variety of tissues. Their purpose is to explore the mechanisms by which age produces alterations of hormone-responsiveness in biological membranes, with special emphasis on the relationship between adenylate cyclase and hormone receptors. Dietary effects on the components of the adenylate cyclase system are also under study. The mechanism of the age-related decrease of catecholamine- sensitive lipolysis is being studied in comparative measurements in two strains of rat (GRC-Wistar and Fisher 344) which exhibit different age-related changes. Aging in fat cells is being studied in tissue culture of pre-adipocytes from these rats. The phenomenon of stress-relatd inhibition of thyrotropin (TSH) secretion and development of low thyroxine (T4) in severely ill humans ("euthyroid sick syndrome") is under study.